ubimkvol: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/sbin/ubimkvol - from package: mtd-utils

You may install the required package with command apt-get install {package}

Error in other languages:
ubimkvol: bevel nie gevind nie
ubimkvol: comandă negăsită
ubimkvol: comando não encontrado
ubimkvol: commande introuvable
ubimkvol: command not found
ubimkvol: käsku ei ole
ubimkvol: không tìm thấy lệnh
ubimkvol: komanda nerasta
ubimkvol: Kommando nicht gefunden.
ubimkvol: kommandot finns inte
ubimkvol: komut yok
ubimkvol: nie znaleziono polecenia
ubimkvol: níor aimsíodh an t-ordú
ubimkvol: no se encontró la orden
ubimkvol: no s'ha trobat l'ordre
ubimkvol: opdracht niet gevonden
ubimkvol: parancs nem található
ubimkvol: perintah tidak ditemukan
ubimkvol: príkaz nenájdený
ubimkvol: příkaz nenalezen
ubimkvol: команда не найдена
ubimkvol: командата не е открита
ubimkvol: 命令找不到
ubimkvol: コマンドが見つかりません